Lin Pingping, An Fengmei, Xu Xia, Zhao Liyan, Liu Liang, Liu Ning, Wang Peipei, Liu Jiao, Wang Le, Li Mingchun
Department of Pharmacology, Medical College of Qingdao University, Qingdao, China.
Hand Surgery Center of the Whole Army, No. 401 Hospital of Chinese People's Liberation Army, Qingdao, China.
Biochem Biophys Res Commun. 2015 May 1;460(2):362-7. doi: 10.1016/j.bbrc.2015.03.039. Epub 2015 Mar 17.
Receptor tyrosine kinases, mediators of a variety of critical cellular functions, contribute to tumor progression and metastasis. The epidermal growth factor receptor (EGFR), a member of the receptor tyrosine kinase family, is ubiquitously expressed on the surface of mammalian cells. Erlotinib hydrochloride (Tarceva) can inhibit the intracellular phosphorylation of tyrosine kinases. To investigate the influence of dosing time on the ability of erlotinib to inhibit tumor growth and the underlying molecular mechanisms via the PI3K/AKT and ERK/MAPK pathway, we established nude mice HCC827 tumor xenografts models. The tumor-bearing mice were housed 3-4 per cage under standardized light/dark cycle conditions (lights on at 07:00 h, off at 19:00 h) with food and water ad libitum. The mice were randomly divided into erlotinib treated groups and control groups, gavaged with erlotinib and vehicle respectively at 6 different time points for 21 days. To draw tumor growth curves, the tumor volume was measured every three days. After the mice were sacrificed, the tumor masses of each group were removed and weighed. The relative protein expression levels of p-EGFR, p-AKT and p-MAPK were assayed at 4 h after erlotinib or vehicle gavage by Western blot analysis. The antitumor effect of erlotinib presented diurnal rhythmicity. The growth of HCC827 xenograft was more potently inhibited by erlotinib in the early light phase than in the early dark phase (p < 0.05). The inhibitory effect of erlotinib on phosphorylation of EGFR, AKT and MAPK varied with its administration time. The results indicate that the antitumor effect of erlotinib is more potent when the drug was administered when the activities of EGFR and its downstream factors increased. Our findings may provide a clue to optimize the dosing schedule of erlotinib.
受体酪氨酸激酶是多种关键细胞功能的介质，有助于肿瘤进展和转移。表皮生长因子受体（EGFR）是受体酪氨酸激酶家族的成员，在哺乳动物细胞表面普遍表达。盐酸厄洛替尼（特罗凯）可抑制酪氨酸激酶的细胞内磷酸化。为了研究给药时间对厄洛替尼抑制肿瘤生长能力的影响以及通过PI3K/AKT和ERK/MAPK途径的潜在分子机制，我们建立了裸鼠HCC827肿瘤异种移植模型。将荷瘤小鼠每笼饲养3 - 4只，置于标准化的光/暗循环条件下（07:00开灯，19:00关灯），自由饮食和饮水。将小鼠随机分为厄洛替尼治疗组和对照组，分别在6个不同时间点给予厄洛替尼和赋形剂灌胃，持续21天。为绘制肿瘤生长曲线，每三天测量一次肿瘤体积。小鼠处死后，取出每组的肿瘤块并称重。通过蛋白质免疫印迹分析在厄洛替尼或赋形剂灌胃后4小时测定p-EGFR、p-AKT和p-MAPK的相对蛋白表达水平。厄洛替尼的抗肿瘤作用呈现昼夜节律性。在光照早期，厄洛替尼对HCC827异种移植瘤生长的抑制作用比黑暗早期更强（p < 0.05）。厄洛替尼对EGFR、AKT和MAPK磷酸化的抑制作用随给药时间而变化。结果表明，当EGFR及其下游因子活性增加时给予厄洛替尼，其抗肿瘤作用更强。我们的发现可能为优化厄洛替尼的给药方案提供线索。
